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<td ><a href="../qtdoc/index.html">Qt 5.14</a></td><td ><a href="qtgui-index.html">Qt GUI</a></td><td ><a href="qtgui-module.html">C++ Classes</a></td><td >QIconEngine</td></tr></table><table class="buildversion"><tr>
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<li class="level1"><a href="#public-types">Public Types</a></li>
<li class="level1"><a href="#public-functions">Public Functions</a></li>
<li class="level1"><a href="#details">Detailed Description</a></li>
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<h1 class="title">QIconEngine Class</h1>
<!-- $$$QIconEngine-brief -->
<p>The QIconEngine class provides an abstract base class for <a href="qicon.html">QIcon</a> renderers. <a href="#details">More...</a></p>
<!-- @@@QIconEngine -->
<div class="table"><table class="alignedsummary">
<tr><td class="memItemLeft rightAlign topAlign"> Header:</td><td class="memItemRight bottomAlign">   <span class="preprocessor">#include &lt;QIconEngine&gt;</span>
</td></tr><tr><td class="memItemLeft rightAlign topAlign"> qmake:</td><td class="memItemRight bottomAlign"> QT += gui</td></tr></table></div><ul>
<li><a href="qiconengine-members.html">List of all members, including inherited members</a></li>
</ul>
<a name="public-types"></a>
<h2 id="public-types">Public Types</h2>
<div class="table"><table class="alignedsummary">
<tr><td class="memItemLeft rightAlign topAlign"> </td><td class="memItemRight bottomAlign"><b><a href="qiconengine-availablesizesargument.html">AvailableSizesArgument</a></b></td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> </td><td class="memItemRight bottomAlign"><b><a href="qiconengine-scaledpixmapargument.html">ScaledPixmapArgument</a></b></td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> enum </td><td class="memItemRight bottomAlign"><b><a href="qiconengine.html#IconEngineHook-enum">IconEngineHook</a></b> { AvailableSizesHook, IconNameHook, IsNullHook, ScaledPixmapHook }</td></tr>
</table></div>
<a name="public-functions"></a>
<h2 id="public-functions">Public Functions</h2>
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<tr><td class="memItemLeft rightAlign topAlign"> </td><td class="memItemRight bottomAlign"><b><a href="qiconengine.html#QIconEngine">QIconEngine</a></b>()</td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> virtual </td><td class="memItemRight bottomAlign"><b><a href="qiconengine.html#dtor.QIconEngine">~QIconEngine</a></b>()</td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> virtual QSize </td><td class="memItemRight bottomAlign"><b><a href="qiconengine.html#actualSize">actualSize</a></b>(const QSize &amp;<i>size</i>, QIcon::Mode <i>mode</i>, QIcon::State <i>state</i>)</td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> virtual void </td><td class="memItemRight bottomAlign"><b><a href="qiconengine.html#addFile">addFile</a></b>(const QString &amp;<i>fileName</i>, const QSize &amp;<i>size</i>, QIcon::Mode <i>mode</i>, QIcon::State <i>state</i>)</td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> virtual void </td><td class="memItemRight bottomAlign"><b><a href="qiconengine.html#addPixmap">addPixmap</a></b>(const QPixmap &amp;<i>pixmap</i>, QIcon::Mode <i>mode</i>, QIcon::State <i>state</i>)</td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> virtual QList&lt;QSize&gt; </td><td class="memItemRight bottomAlign"><b><a href="qiconengine.html#availableSizes">availableSizes</a></b>(QIcon::Mode <i>mode</i> = QIcon::Normal, QIcon::State <i>state</i> = QIcon::Off) const</td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> virtual QIconEngine *</td><td class="memItemRight bottomAlign"><b><a href="qiconengine.html#clone">clone</a></b>() const = 0</td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> virtual QString </td><td class="memItemRight bottomAlign"><b><a href="qiconengine.html#iconName">iconName</a></b>() const</td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> bool </td><td class="memItemRight bottomAlign"><b><a href="qiconengine.html#isNull">isNull</a></b>() const</td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> virtual QString </td><td class="memItemRight bottomAlign"><b><a href="qiconengine.html#key">key</a></b>() const</td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> virtual void </td><td class="memItemRight bottomAlign"><b><a href="qiconengine.html#paint">paint</a></b>(QPainter *<i>painter</i>, const QRect &amp;<i>rect</i>, QIcon::Mode <i>mode</i>, QIcon::State <i>state</i>) = 0</td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> virtual QPixmap </td><td class="memItemRight bottomAlign"><b><a href="qiconengine.html#pixmap">pixmap</a></b>(const QSize &amp;<i>size</i>, QIcon::Mode <i>mode</i>, QIcon::State <i>state</i>)</td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> virtual bool </td><td class="memItemRight bottomAlign"><b><a href="qiconengine.html#read">read</a></b>(QDataStream &amp;<i>in</i>)</td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> QPixmap </td><td class="memItemRight bottomAlign"><b><a href="qiconengine.html#scaledPixmap">scaledPixmap</a></b>(const QSize &amp;<i>size</i>, QIcon::Mode <i>mode</i>, QIcon::State <i>state</i>, qreal <i>scale</i>)</td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> virtual void </td><td class="memItemRight bottomAlign"><b><a href="qiconengine.html#virtual_hook">virtual_hook</a></b>(int <i>id</i>, void *<i>data</i>)</td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> virtual bool </td><td class="memItemRight bottomAlign"><b><a href="qiconengine.html#write">write</a></b>(QDataStream &amp;<i>out</i>) const</td></tr>
</table></div>
<a name="details"></a>
<!-- $$$QIconEngine-description -->
<div class="descr">
<h2 id="details">Detailed Description</h2>
<p>An icon engine provides the rendering functions for a <a href="qicon.html">QIcon</a>. Each icon has a corresponding icon engine that is responsible for drawing the icon with a requested size, mode and state.</p>
<p>The icon is rendered by the <a href="qiconengine.html#paint">paint</a>() function, and the icon can additionally be obtained as a pixmap with the <a href="qiconengine.html#pixmap">pixmap</a>() function (the default implementation simply uses <a href="qiconengine.html#paint">paint</a>() to achieve this). The <a href="qiconengine.html#addPixmap">addPixmap</a>() function can be used to add new pixmaps to the icon engine, and is used by <a href="qicon.html">QIcon</a> to add specialized custom pixmaps.</p>
<p>The <a href="qiconengine.html#paint">paint</a>(), <a href="qiconengine.html#pixmap">pixmap</a>(), and <a href="qiconengine.html#addPixmap">addPixmap</a>() functions are all virtual, and can therefore be reimplemented in subclasses of QIconEngine.</p>
</div>
<p><b>See also </b><a href="qiconengineplugin.html">QIconEnginePlugin</a>.</p>
<!-- @@@QIconEngine -->
<div class="types">
<h2>Member Type Documentation</h2>
<!-- $$$IconEngineHook$$$AvailableSizesHook$$$IconNameHook$$$IsNullHook$$$ScaledPixmapHook -->
<h3 class="fn" id="IconEngineHook-enum"><a name="IconEngineHook-enum"></a>enum QIconEngine::<span class="name">IconEngineHook</span></h3>
<p>These enum values are used for <a href="qiconengine.html#virtual_hook">virtual_hook</a>() to allow additional queries to icon engine without breaking binary compatibility.</p>
<div class="table"><table class="valuelist"><tr valign="top" class="odd"><th class="tblConst">Constant</th><th class="tblval">Value</th><th class="tbldscr">Description</th></tr>
<tr><td class="topAlign"><code>QIconEngine::AvailableSizesHook</code></td><td class="topAlign tblval"><code>1</code></td><td class="topAlign">Allows to query the sizes of the contained pixmaps for pixmap-based engines. The <i>data</i> argument of the <a href="qiconengine.html#virtual_hook">virtual_hook</a>() function is a <a href="qiconengine-availablesizesargument.html">AvailableSizesArgument</a> pointer that should be filled with icon sizes. Engines that work in terms of a scalable, vectorial format normally return an empty list.</td></tr>
<tr><td class="topAlign"><code>QIconEngine::IconNameHook</code></td><td class="topAlign tblval"><code>2</code></td><td class="topAlign">Allows to query the name used to create the icon, for example when instantiating an icon using <a href="qicon.html#fromTheme">QIcon::fromTheme</a>().</td></tr>
<tr><td class="topAlign"><code>QIconEngine::IsNullHook</code></td><td class="topAlign tblval"><code>3</code></td><td class="topAlign">Allow to query if this engine represents a null icon. The <i>data</i> argument of the <a href="qiconengine.html#virtual_hook">virtual_hook</a>() is a pointer to a bool that can be set to true if the icon is null. This enum value was added in Qt 5.7&#x2e;</td></tr>
<tr><td class="topAlign"><code>QIconEngine::ScaledPixmapHook</code></td><td class="topAlign tblval"><code>4</code></td><td class="topAlign">Provides a way to get a pixmap that is scaled according to the given scale (typically equal to the <a href="../qtdoc/highdpi.html#glossary-of-high-dpi-terms">device pixel ratio</a>). The <i>data</i> argument of the <a href="qiconengine.html#virtual_hook">virtual_hook</a>() function is a <a href="qiconengine-scaledpixmapargument.html">ScaledPixmapArgument</a> pointer that contains both the input and output arguments. This enum value was added in Qt 5.9&#x2e;</td></tr>
</table></div>
<p>This enum was introduced or modified in Qt 4.5.</p>
<p><b>See also </b><a href="qiconengine.html#virtual_hook">virtual_hook</a>().</p>
<!-- @@@IconEngineHook -->
</div>
<div class="func">
<h2>Member Function Documentation</h2>
<!-- $$$QIconEngine[overload1]$$$QIconEngine -->
<h3 class="fn" id="QIconEngine"><a name="QIconEngine"></a>QIconEngine::<span class="name">QIconEngine</span>()</h3>
<p>Constructs the icon engine.</p>
<p>This function was introduced in Qt 5.6.</p>
<!-- @@@QIconEngine -->
<!-- $$$~QIconEngine[overload1]$$$~QIconEngine -->
<h3 class="fn" id="dtor.QIconEngine"><a name="dtor.QIconEngine"></a><code>[virtual] </code>QIconEngine::<span class="name">~QIconEngine</span>()</h3>
<p>Destroys the icon engine.</p>
<!-- @@@~QIconEngine -->
<!-- $$$actualSize[overload1]$$$actualSizeconstQSize&QIcon::ModeQIcon::State -->
<h3 class="fn" id="actualSize"><a name="actualSize"></a><code>[virtual] </code><span class="type"><a href="../qtcore/qsize.html">QSize</a></span> QIconEngine::<span class="name">actualSize</span>(const <span class="type"><a href="../qtcore/qsize.html">QSize</a></span> &amp;<i>size</i>, <span class="type"><a href="qicon.html#Mode-enum">QIcon::Mode</a></span> <i>mode</i>, <span class="type"><a href="qicon.html#State-enum">QIcon::State</a></span> <i>state</i>)</h3>
<p>Returns the actual size of the icon the engine provides for the requested <i>size</i>, <i>mode</i> and <i>state</i>. The default implementation returns the given <i>size</i>.</p>
<!-- @@@actualSize -->
<!-- $$$addFile[overload1]$$$addFileconstQString&constQSize&QIcon::ModeQIcon::State -->
<h3 class="fn" id="addFile"><a name="addFile"></a><code>[virtual] </code><span class="type">void</span> QIconEngine::<span class="name">addFile</span>(const <span class="type"><a href="../qtcore/qstring.html">QString</a></span> &amp;<i>fileName</i>, const <span class="type"><a href="../qtcore/qsize.html">QSize</a></span> &amp;<i>size</i>, <span class="type"><a href="qicon.html#Mode-enum">QIcon::Mode</a></span> <i>mode</i>, <span class="type"><a href="qicon.html#State-enum">QIcon::State</a></span> <i>state</i>)</h3>
<p>Called by <a href="qicon.html#addFile">QIcon::addFile</a>(). Adds a specialized pixmap from the file with the given <i>fileName</i>, <i>size</i>, <i>mode</i> and <i>state</i>. The default pixmap-based engine stores any supplied file names, and it loads the pixmaps on demand instead of using scaled pixmaps if the size of a pixmap matches the size of icon requested. Custom icon engines that implement scalable vector formats are free to ignores any extra files.</p>
<!-- @@@addFile -->
<!-- $$$addPixmap[overload1]$$$addPixmapconstQPixmap&QIcon::ModeQIcon::State -->
<h3 class="fn" id="addPixmap"><a name="addPixmap"></a><code>[virtual] </code><span class="type">void</span> QIconEngine::<span class="name">addPixmap</span>(const <span class="type"><a href="qpixmap.html">QPixmap</a></span> &amp;<i>pixmap</i>, <span class="type"><a href="qicon.html#Mode-enum">QIcon::Mode</a></span> <i>mode</i>, <span class="type"><a href="qicon.html#State-enum">QIcon::State</a></span> <i>state</i>)</h3>
<p>Called by <a href="qicon.html#addPixmap">QIcon::addPixmap</a>(). Adds a specialized <i>pixmap</i> for the given <i>mode</i> and <i>state</i>. The default pixmap-based engine stores any supplied pixmaps, and it uses them instead of scaled pixmaps if the size of a pixmap matches the size of icon requested. Custom icon engines that implement scalable vector formats are free to ignores any extra pixmaps.</p>
<!-- @@@addPixmap -->
<!-- $$$availableSizes[overload1]$$$availableSizesQIcon::ModeQIcon::State -->
<h3 class="fn" id="availableSizes"><a name="availableSizes"></a><code>[virtual] </code><span class="type">QList</span>&lt;<span class="type"><a href="../qtcore/qsize.html">QSize</a></span>&gt; QIconEngine::<span class="name">availableSizes</span>(<span class="type"><a href="qicon.html#Mode-enum">QIcon::Mode</a></span> <i>mode</i> = QIcon::Normal, <span class="type"><a href="qicon.html#State-enum">QIcon::State</a></span> <i>state</i> = QIcon::Off) const</h3>
<p>Returns sizes of all images that are contained in the engine for the specific <i>mode</i> and <i>state</i>.</p>
<p><b>Note: </b>This is a helper method and the actual work is done by the <a href="qiconengine.html#virtual_hook">virtual_hook</a>() method, hence this method depends on icon engine support and may not work with all icon engines.</p><p>This function was introduced in Qt 4.5.</p>
<!-- @@@availableSizes -->
<!-- $$$clone[overload1]$$$clone -->
<h3 class="fn" id="clone"><a name="clone"></a><code>[pure virtual] </code><span class="type"><a href="qiconengine.html#QIconEngine">QIconEngine</a></span> *QIconEngine::<span class="name">clone</span>() const</h3>
<p>Reimplement this method to return a clone of this icon engine.</p>
<!-- @@@clone -->
<!-- $$$iconName[overload1]$$$iconName -->
<h3 class="fn" id="iconName"><a name="iconName"></a><code>[virtual] </code><span class="type"><a href="../qtcore/qstring.html">QString</a></span> QIconEngine::<span class="name">iconName</span>() const</h3>
<p>Returns the name used to create the engine, if available.</p>
<p><b>Note: </b>This is a helper method and the actual work is done by the <a href="qiconengine.html#virtual_hook">virtual_hook</a>() method, hence this method depends on icon engine support and may not work with all icon engines.</p><p>This function was introduced in Qt 4.7.</p>
<!-- @@@iconName -->
<!-- $$$isNull[overload1]$$$isNull -->
<h3 class="fn" id="isNull"><a name="isNull"></a><span class="type">bool</span> QIconEngine::<span class="name">isNull</span>() const</h3>
<p>Returns true if this icon engine represent a null <a href="qicon.html">QIcon</a>.</p>
<p><b>Note: </b>This is a helper method and the actual work is done by the <a href="qiconengine.html#virtual_hook">virtual_hook</a>() method, hence this method depends on icon engine support and may not work with all icon engines.</p><p>This function was introduced in Qt 5.7.</p>
<!-- @@@isNull -->
<!-- $$$key[overload1]$$$key -->
<h3 class="fn" id="key"><a name="key"></a><code>[virtual] </code><span class="type"><a href="../qtcore/qstring.html">QString</a></span> QIconEngine::<span class="name">key</span>() const</h3>
<p>Returns a key that identifies this icon engine.</p>
<!-- @@@key -->
<!-- $$$paint[overload1]$$$paintQPainter*constQRect&QIcon::ModeQIcon::State -->
<h3 class="fn" id="paint"><a name="paint"></a><code>[pure virtual] </code><span class="type">void</span> QIconEngine::<span class="name">paint</span>(<span class="type"><a href="qpainter.html">QPainter</a></span> *<i>painter</i>, const <span class="type"><a href="../qtcore/qrect.html">QRect</a></span> &amp;<i>rect</i>, <span class="type"><a href="qicon.html#Mode-enum">QIcon::Mode</a></span> <i>mode</i>, <span class="type"><a href="qicon.html#State-enum">QIcon::State</a></span> <i>state</i>)</h3>
<p>Uses the given <i>painter</i> to paint the icon with the required <i>mode</i> and <i>state</i> into the rectangle <i>rect</i>.</p>
<!-- @@@paint -->
<!-- $$$pixmap[overload1]$$$pixmapconstQSize&QIcon::ModeQIcon::State -->
<h3 class="fn" id="pixmap"><a name="pixmap"></a><code>[virtual] </code><span class="type"><a href="qpixmap.html">QPixmap</a></span> QIconEngine::<span class="name">pixmap</span>(const <span class="type"><a href="../qtcore/qsize.html">QSize</a></span> &amp;<i>size</i>, <span class="type"><a href="qicon.html#Mode-enum">QIcon::Mode</a></span> <i>mode</i>, <span class="type"><a href="qicon.html#State-enum">QIcon::State</a></span> <i>state</i>)</h3>
<p>Returns the icon as a pixmap with the required <i>size</i>, <i>mode</i>, and <i>state</i>. The default implementation creates a new pixmap and calls <a href="qiconengine.html#paint">paint</a>() to fill it.</p>
<!-- @@@pixmap -->
<!-- $$$read[overload1]$$$readQDataStream& -->
<h3 class="fn" id="read"><a name="read"></a><code>[virtual] </code><span class="type">bool</span> QIconEngine::<span class="name">read</span>(<span class="type"><a href="../qtcore/qdatastream.html">QDataStream</a></span> &amp;<i>in</i>)</h3>
<p>Reads icon engine contents from the <a href="../qtcore/qdatastream.html">QDataStream</a> <i>in</i>. Returns true if the contents were read; otherwise returns <code>false</code>.</p>
<p><a href="qiconengine.html">QIconEngine</a>'s default implementation always return false.</p>
<!-- @@@read -->
<!-- $$$scaledPixmap[overload1]$$$scaledPixmapconstQSize&QIcon::ModeQIcon::Stateqreal -->
<h3 class="fn" id="scaledPixmap"><a name="scaledPixmap"></a><span class="type"><a href="qpixmap.html">QPixmap</a></span> QIconEngine::<span class="name">scaledPixmap</span>(const <span class="type"><a href="../qtcore/qsize.html">QSize</a></span> &amp;<i>size</i>, <span class="type"><a href="qicon.html#Mode-enum">QIcon::Mode</a></span> <i>mode</i>, <span class="type"><a href="qicon.html#State-enum">QIcon::State</a></span> <i>state</i>, <span class="type"><a href="../qtcore/qtglobal.html#qreal-typedef">qreal</a></span> <i>scale</i>)</h3>
<p>Returns a pixmap for the given <i>size</i>, <i>mode</i>, <i>state</i> and <i>scale</i>.</p>
<p>The <i>scale</i> argument is typically equal to the <a href="../qtdoc/highdpi.html#glossary-of-high-dpi-terms">device pixel ratio</a> of the display.</p>
<p><b>Note: </b>This is a helper method and the actual work is done by the <a href="qiconengine.html#virtual_hook">virtual_hook</a>() method, hence this method depends on icon engine support and may not work with all icon engines.</p><p><b>Note: </b>Some engines may cast <i>scale</i> to an integer.</p><p>This function was introduced in Qt 5.9.</p>
<p><b>See also </b><a href="qiconengine-scaledpixmapargument.html">ScaledPixmapArgument</a>.</p>
<!-- @@@scaledPixmap -->
<!-- $$$virtual_hook[overload1]$$$virtual_hookintvoid* -->
<h3 class="fn" id="virtual_hook"><a name="virtual_hook"></a><code>[virtual] </code><span class="type">void</span> QIconEngine::<span class="name">virtual_hook</span>(<span class="type">int</span> <i>id</i>, <span class="type">void</span> *<i>data</i>)</h3>
<p>Additional method to allow extending <a href="qiconengine.html">QIconEngine</a> without adding new virtual methods (and without breaking binary compatibility). The actual action and format of <i>data</i> depends on <i>id</i> argument which is in fact a constant from <a href="qiconengine.html#IconEngineHook-enum">IconEngineHook</a> enum.</p>
<p>This function was introduced in Qt 4.5.</p>
<p><b>See also </b><a href="qiconengine.html#IconEngineHook-enum">IconEngineHook</a>.</p>
<!-- @@@virtual_hook -->
<!-- $$$write[overload1]$$$writeQDataStream& -->
<h3 class="fn" id="write"><a name="write"></a><code>[virtual] </code><span class="type">bool</span> QIconEngine::<span class="name">write</span>(<span class="type"><a href="../qtcore/qdatastream.html">QDataStream</a></span> &amp;<i>out</i>) const</h3>
<p>Writes the contents of this engine to the <a href="../qtcore/qdatastream.html">QDataStream</a> <i>out</i>. Returns <code>true</code> if the contents were written; otherwise returns <code>false</code>.</p>
<p><a href="qiconengine.html">QIconEngine</a>'s default implementation always return false.</p>
<!-- @@@write -->
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